More data type fixes for <tailbone-datepicker>

traditionally the caller has always dealt with string values only, so
the component should never emit events with date values, etc.

tailbone/static/js/tailbone.buefy.datepicker.js

@@ -27,20 +27,14 @@ const TailboneDatepicker = {
     },
 
     data() {
-        let buefyValue = this.value
-        if (buefyValue && !buefyValue.getDate) {
-            buefyValue = this.parseDate(this.value)
-        }
         return {
-            buefyValue,
+            buefyValue: this.parseDate(this.value),
         }
     },
 
     watch: {
         value(to, from) {
-            if (this.buefyValue != to) {
-                this.buefyValue = to
-            }
+            this.buefyValue = this.parseDate(to)
         },
     },
 
@@ -61,13 +55,16 @@ const TailboneDatepicker = {
         },
 
         parseDate(date) {
-            // note, this assumes classic YYYY-MM-DD (i.e. ISO?) format
-            var parts = date.split('-')
-            return new Date(parts[0], parseInt(parts[1]) - 1, parts[2])
+            if (typeof(date) == 'string') {
+                // note, this assumes classic YYYY-MM-DD (i.e. ISO?) format
+                var parts = date.split('-')
+                return new Date(parts[0], parseInt(parts[1]) - 1, parts[2])
+            }
+            return date
         },
 
         dateChanged(date) {
-            this.$emit('input', date)
+            this.$emit('input', this.formatDate(date))
         },
 
         focus() {